Books are increasingly purchased electronically through online sources, and consumed on electronic devices. When reading a book on an electronic device, a user's experience can be enhanced by features such as annotations. Annotations may include highlighting, underlining, commenting, editing, and so forth, and may be enabled by electronic book reader hardware and software.
In some environments, users may have their annotations collected and reported to a central web service, such as the service from which the users have purchased their electronic books. This enables the annotations to be archived on behalf of the users, and for the users to transfer their annotations to different reader devices.
Users may also in some environments share their annotations with other users. In some situations, the central web service may aggregate annotations from users, and may share the aggregated annotations with other users so that people can see what others have found interesting or noteworthy in an electronic book.
For example, an individual user may choose to share their personal annotations with one or more friends. Similarly, users may subscribe to the annotations or notes created by another person. In addition, a service may analyze collected annotations from different people, identify the most popular annotations, and distribute those annotations to users who choose to see them.